Electron Paramagnetic Resonance (EPR) Studies already carried out in this project have obtained evidence that there are quantitative and qualitative differences between ceruloplasmin (CP) in serum from cancer patients and non-cancerous volunteers. It is proposed to continue a comprehensive research program designed to investigate the use of EPR as a screening technique for early detection of cancer and to utilize EPR spin labeling techniques to elucidate possible membrane and viscosity changes which may occur in blood constituents of humans with cancer. A double-blind study will continue to be carried out on the signal intensity of Cu ion bound to CP (Cu ion-CP) in serum from female patients with suspicious breast masses prior to breast biopsy. Total Cu levels of the serum samples will be measured by atomic absorption spectroscopy so that ratios of Cu ion-CP/total Cu can be calculated. The Cu ion-CP levels and Cu ion-CP/total Cu ratios will be tested by statistical methods to substantiate differences already found between serum samples from females with benign breast masses and those from females with malignant breast masses. These same kinds of measurements will be applied to a population of asymptomatic women volunteers who have been selected for high risk of breast cancer from the Kansas University Medical Center breast cancer screening demonstration program. The sensitivity, specificity, and predictive value positive of the methods will be determined. A similar study will be carried out on a selected population of male smoking former asbestos worker volunteers who are at very high risk for lung cancer. Spin labeling studies will be carried out on isolated lymphocytes to determine whether membrane fluidity or cytoplasmic viscosity changes associated with cancer can be detected. Animal tumor model systems already developed will continue to be studied to learn how early the changes in Cu ion-CP level and in the ratio Cu ion CP/total Cu occur and to obtain more information on possible reasons for these changes in CP.